Number of UNITS in the Ecolab Stock Fund of the Ecolab Savings Plan (401(k) Plan) as of December 31, 2011. (The 1599.490 UNITS are the equivalent of approximately 2,976 shares of the issuer's Common Stock.)

(
2)

The phantom stock units represent employer-matching contributions and dividends thereon accrued under the Ecolab Mirror Savings Plan and are to be settled in cash, on a 1-for-1 basis, upon termination of the reporting person's employment. (The 347.686 UNITS are the equivalent of approximately 647 shares of the issuer's Common Stock.)

(
3)

Option granted under the Ecolab Inc. 2002 Stock Incentive Plan on December 11, 2003. The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
4)

Option granted under the Ecolab Inc. 2002 Stock Incentive Plan on December 9, 2004. The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
5)

Option granted under the Ecolab Inc. 2002 Stock Incentive Plan on December 7, 2005. The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
6)

Option granted under the Ecolab Inc. 2005 Stock Incentive Plan on December 6, 2006. The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
7)

Option granted under the Ecolab Inc. 2005 Stock Incentive Plan on December 5, 2007. The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
8)

Option granted under the Ecolab Inc. 2005 Stock Incentive Plan on December 3, 2008. The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
9)

Option granted under the Ecolab Inc. 2005 Stock Incentive Plan on December 2, 2009. The option will become exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
10)

Option granted under the Ecolab Inc. 2010 Stock Incentive Plan on December 1, 2010. The option will become exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.

(
11)

Option granted under the Ecolab Inc. 2010 Stock Incentive Plan on December 1, 2011. The option will become exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining option shares on the third anniversary of the date of grant.